1. Field of the Invention
The present invention relates to a line thermal head printer apparatus in which a line thermal head is supplied with electricity to print on a moving object to be printed, using a ribbon tape (carbon tape).
2. Description of the Related Art
In recent years, there have been many cases where printing of letters and marks, such as date of manufacture, tastable time period, series number of manufacture, etc. on a packaging material for example, have been required to be made on the object to be printed, and for this kind of printing, a line thermal head printer apparatus is often used.
In the conventional line thermal head printer apparatus, a ribbon tape of the same length as the moving length of the object to be printed, such as a film supplied from a master roll, is fed with the same velocity as the moving object to be printed. In this type of line thermal head printer apparatus, a large amount of the expensive ribbon tape is consumed, and so there is a need to reduce the amount of ribbon tape which is used. There has therefore been proposed a device in which a ribbon tape is moved only during printing, and is otherwise stopped.
The velocity of the ribbon tape should always be the same as the object being printed during a printing operation. However, when the movement of the ribbon tape is commenced upon the approach of the portion to be printed of the object to be printed, some rise time is required until the ribbon tape reaches the velocity of the moving object. Moreover, the transfer velocity of the object to be printed varied slightly. Thus there occurs a deviation in the relative position of the object to be printed and the ribbon tape, and a print is not always cleanly applied to a predetermined part of the object to be printed.